The long-term objective of my research is to define the relationship between gene structure and gene expression in eukaryotic cells. The objective of this proposal is to employ a relatively simple gene system in a study of traascriptional control as the first step in understanding regulation of gene transcription in more complex systems. I have chosen to initiate these studies on a set of inducible genes in Drosophila, the heat shock gene system. The central objective of this research proposal is to examine aspects of chromosome structure at both the protein and DNA level that are correlated with control of heat shock gene transcription. This will be accomplished through a two-dimensional approach. The transcriptional unit of different heat shock genes will be physically mapped on fragments of the Drosophila genome that I have isolated as recombinant DNA clones and the nucleotide sequence relationships examined at potential regulatory sites. The second level of investigation will be to probe the gene regions for structural alterations in chromatin that parallel the induction of gene transcription. The completion of these studies will allow me to identify the precise regions of the chromosome that play a role in control of heat shock gene transcription and also to begin to understand the nature of the regulatory process. Future research projects will build on the results of the current proposal and will deal with the actual mechanisms of transcriptional control of the heat shock genes.